It is the broad goal of this study to provide for the first time a normative data base chronicling the relationship between reproductive hormones and mood in the menstrual cycle. We will study these relationships in a narrowly defined population of normal women with and without consistent cyclical changes in mood during the menstral cycle. Specifically, we will: 1. Examine women with a daily mood questionnaire for three cycles to: a. determine whether there is a population of normal women with consistent cyclical mood changes during the menstrual cycle. 2. a. determine whether there is a relationship between any observed mood changes and the patterns of cyclical changes in reproductive hormone plasma concentrations (LH, FSH, estradiol and progesterone) in these women. b. compare these relationships in the women with and without consistent cyclical changes in mood during the cycle. It has been hypothesized that the cyclical changes in mood that have been observed in the menstrual cycle may be due to a common neuroendocrine pathway which regulates both mood and steroid hormone concentrations. An examination of the relationship between mood changes and reproductive hormone dynamics during the menstrual cycle should provide some insight into these important neuroendocrine pathways. It could also provide us with an understanding of the etiology of premenstrual symptomatology and may suggest a treatment for symptoms which are distressful to many women.